A front jaw, in which an adjustment of the elevational position of the sole holders to the height of the sole of the shoe is possible by swivelling the upper part of the housing relative to the lower part of the housing, is disclosed in DE-OS 39 37 363. The upper part of the housing is in this conventional front jaw designed in one piece with the lower part of the housing, with a flexible area being provided in the front area of the jaw, which flexible area makes possible a limited swivelling of the upper part of the front jaw to adjust the position of the sole down-holding means to the height of the sole. This flexible area is produced by a horizontal slot, which is constructed in the front part of the jaw between the release spring and the upper surface of the ski. The locking means is realized on the one hand by a rearwardly projecting nose constructed in one piece with the upper part of the housing, and on the other hand by a spring-loaded rocking lever supported in the lower part of the housing, or a forwardly projecting nose constructed in one piece with the lower part of the housing.
Such a device has a number of disadvantages. The strength of the housing of the ski binding is weakened with the above-identified slot, thus material fatigue can easily occur followed by a breakage of the housing. Furthermore, the swivelling capability of the housing is blocked when this slot gets dirty or ices up, with the danger of breakage being additionally increased by an overload on the sole down-holding means. The front jaw has furthermore a complex design because of the locking means, which is formed thereon in one piece, and is therefore expensive to manufacture.
A front jaw consisting of two housing parts, which is assembled around a transverse axis by swivelling one housing part relative to the other, has become known from DE-OS 39 42 157. The two housing parts are then in the position of use screwed together by means of a vertically arranged screw, with the elevational adjustment of the sole holders being carried out at the same time by means of this screw. This screw and the counterthread provided in the lower part of the housing thus form the locking means for this conventional front jaw. A disadvantage of this device is that the sole holders, when using different ski shoes, must be newly adjusted for each shoe by a serviceman. Moreover, a structurally favorable arrangement of the release spring is prevented by the screw, which, viewed from above, is centrally arranged.
A further device, which enables a change of the elevational position of the sole down-holding means of a front jaw, is described in AT-PS 361 823. A down-holding arm loaded by a spring is in this device pivotally arranged above the release spring on a transverse axis. Elevationally adjustable sole down-holding means are mounted on the down-holding arm. The elevational change of the sole down-holding means created by pivoting the down-holding arm, however, is used in this device to free the ski shoe in upward direction in the case of a release, and not to adjust the ski binding to different soles of shoes, which continues to be done by means of adjusting screws. This device is thus not suited for an automatic adjustment of the sole down-holding means to different soles of shoes, and has furthermore disadvantages, for example, the lateral sole mountings and the sole down-holding means cannot be constructed in one piece.
The orderly functioning of a front jaw of a ski binding depends very much on its correct adjustment. Particularly critical is the adjustment of the height of the sole holders which in most cases is carried out by a service technician. This adjustment is very time-consuming, since it must be extremely exact in order not to influence the release behavior of the front jaw.